This invention relates generally to refrigerant systems, and more particularly to a method for controlling a compressor speed in the refrigerant system.
Modern refrigerators typically include a compressor, an evaporator, and a condenser in a closed refrigeration circuit, and a number of fans that facilitate the refrigeration circuit and direct cooled air into refrigeration compartments. Conventionally, the compressor, evaporator and condenser are operated at a single speed, and a plurality of single speed fans are employed in association with the condenser, evaporator, condenser and also to direct cooled air throughout the refrigerator. Collectively, these components are sometimes referred to as a sealed system. While these single speed sealed systems have been satisfactory in the past, they are now perceived as disadvantageous in several aspects.
For example, such single speed systems often entail considerable temperature variation in operation of the refrigerator as the sealed system cycles on an off. Further, the refrigerator can sometimes be undesirably noisy as it cycles from an off or relatively silent condition to an on condition with the sealed system components energized. In addition, single speed systems are not as energy efficient as desired.
While most of these disadvantages can be addressed by using multiple speed or variable speed fans and sealed system components, use of variable speed components complicates the refrigeration controls considerably. A number of operating states corresponding to different combinations of the components at various speeds is virtually infinite, and finding and maintaining an optimal refrigerator state in an energy efficient manner can be formidable task. Additionally, manipulating component speeds in an energy efficient manner while responding to changing operating conditions and environments, such as door open events and ambient temperature fluctuation, is a challenge.
In one aspect, a method for controlling a sealed system including a variable speed compressor coupled to a controller is provided. The method includes defining a first set of temperature ranges for operating the compressor during a temperature increase period, defining a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges, and operating the compressor using the defined first set and the defined second set.
In another aspect, a method for controlling a sealed system including a variable speed compressor coupled to a controller is provided. The method includes defining a first set of temperature ranges for operating the compressor during a temperature increase period including a low temperature range for operating the compressor in a low speed, a medium temperature range for operating the compressor in a medium speed, and a high temperature range for operating the compressor in a high speed, and defining a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges. The method also includes operating the compressor in a high speed until a low temperature range threshold is reached, operating the compressor in a medium speed until a set-point upper hysteresis is reached, and operating the compressor in a low speed until a set-point lower hysteresis is reached.
In another aspect, a refrigeration device is provided. The refrigeration device includes a compressor operable in a multiplicity of speeds, a condenser fan operable in a multiplicity of speeds, an evaporator fan operable in a multiplicity of speeds, a controller operatively coupled to at least one of the compressor, the condenser fan, and the evaporator fan. The controller includes a first set of temperature ranges for operating at least one of the compressor, the condenser fan, and the evaporator fan during a temperature increase period and a second set of temperature ranges for operating at least one of the compressor, the condenser fan, and the evaporator fan during a temperature decrease period, the second set of ranges different than the first set of ranges, and a thermistor coupled to the controller, the controller configured to operate at least one of the compressor, the condenser fan, and the evaporator fan using the first set of ranges and the second set of ranges.
In another aspect, a refrigeration device including a compressor operable in a multiplicity of speeds and a controller operatively coupled the compressor is provided. The controller includes a first set of temperature ranges for operating the compressor during a temperature increase period and a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges, and a thermistor coupled to the controller. The controller is configured to define a first set of temperature ranges for operating the compressor during a temperature increase period, the first set of temperature ranges including a low temperature range for operating the compressor in a low speed, a medium temperature range for operating the compressor in a medium speed, and a high temperature range for operating the compressor in a high speed, define a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges, and operate the compressor in a high speed until a low temperature range threshold is reached, operate the compressor in a medium speed until a set-point upper hysteresis is reached, and operate the compressor in a low speed until a set-point lower hysteresis is reached.
In another aspect, a control system for a refrigeration system is provided. The refrigeration system includes a fresh food compartment and a freezer compartment with a damper establishing flow communication therebetween, a sealed system for forcing cold air through the refrigerator compartments, the sealed system including a compressor, a condenser, an evaporator fan and a fresh food compartment fan. The control system includes a controller operatively coupled to the damper, the compressor, the condenser fan, the evaporator fan and the fresh food fan, the controller including a first set of temperature ranges for operating the compressor during a temperature increase period and a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges, and a thermistor coupled to the controller, the controller configured to operate the compressor using the first set of ranges and the second set of ranges.
In another aspect, a control system for a refrigeration system is provided. The refrigeration system includes a fresh food compartment and a freezer compartment with a damper establishing flow communication therebetween, a sealed system for forcing cold air through the refrigerator compartments, the sealed system including a compressor, a condenser, an evaporator fan and a fresh food compartment fan. The control system includes a controller operatively coupled to the damper, the compressor, the condenser fan, the evaporator fan and the fresh food fan, the controller including a first set of temperature ranges for operating the compressor during a temperature increase period and a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges, and a thermistor coupled to the controller. The controller is configured to define a first set of temperature ranges for operating the compressor during a temperature increase period, the first set of temperature ranges including a low temperature range for operating the compressor in a low speed, a medium temperature range for operating the compressor in a medium speed, and a high temperature range for operating the compressor in a high speed, define a second set of temperature ranges for operating the compressor during a temperature decrease period, the second set of ranges different than the first set of ranges. The controller is also configured to operate the compressor in a high speed until a low temperature range threshold is reached, operate the compressor in a medium speed until a set-point upper hysteresis is reached, and operate the compressor in a low speed until a set-point lower hysteresis is reached.